The overall objective of this project is a biosystematic study of the mosquito genus Toxorhynchites, culminating in a monograph of the Toxorhynchites of the World. The final publication would include complete descriptions of all known stages, illustrations of larvae, pupae and portions of the adult, distribution, bionomics of all species and keys to all stages. An annotated bibliography of the more than 1000 references to Toxorhynchites designed to serve the broadest possible user community will be published. We hope to incorporate the best aspects of the techniques of cladistic, intutitive and numerical taxonomy applied to a broad range of character sets including morphological, biological, geographical, ecological, cytogenetic and biochemical characters. The numerical taxonomic study involves the processing and analysis of morphometric data using multivariate procedures which include character standardization, computation of similarity coefficients, cluster analysis and ordination by similarity coefficients, cluster analysis and ordination by principal component analysis and multidimensional scaling.